The pyrometallurgical production of copper generates stags, a residue with a significant content of this metal. Copper can be recovered from the slags by froth flotation after cooling, crushing, and grinding. The obtained Cu-concentrate is sent to the pyrometallurgical process. If grinding is not fine enough for efficient flotation, copper is lost in tailings. In this paper, the ferric leaching of slag flotation tailings is studied. Copper extractions of 66% are achieved by ferric leaching, and Cu content in tailings is reduced from 0.78% to 0.24%. (C) 2008 Elsevier Ltd. All rights reserved.